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Page:Popular Science Monthly Volume 90.djvu/391

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The Way of a Bird in the Air

A gigantic artificial dove and the lesson that it teaches

��MORE than twenty years ago, Otto Lillienthal, a German engineer, be- came interested in flying. He was one of the first scientific pioneers of the aeroplane. For weeks and weeks at a time,- he would watch storks in motion. To him, birds were masters from whom ignor- ant man must learn if he, too, would fly.

Lillienthal's first step, after long watch- ing was to build a motor-less machine of a

��to the air, and that, after all, the bird idea was inherently correct. All the latest machines look very much like birds because they have been provided with bird-like bodies in which passengers and engines are carried.

A New England inventor, Percival White,

has very wisely taken up Lillienthal's line

of investigation and has built an exact

gigantic copy of a carrier pigeon. His

glider is an object lesson. His huge

bird shows how sweet are the lines of

Nature's flying machines and how

���Percival White's gigantic copy of a carrier pigeon. It has landing skids under the body and a drag post under each wing for easy alighting. The wings are pivoted and swing easily

��type which has since come to be called a glider, a kind of artificial bird, consisting primarily of a pair of canvas wings stretched on a frame. He would run down a hill with this apparatus. After he had acquired sufficient momentum, he would draw up his legs, glide along freely for perhaps a hundred yards, and come to earth.

This performance was not so easy as it seems. Even on the calmest days, the wind tended to upset his apparatus. Lillienthal had to throw himself bodily from side to side to maintain his balance. He had to be very quick — just as quick as the wind. He made many hundred flights and learned a great deal about soaring. But one day, he was not quick enough. The wind upset him, and he was killed — one of the first martyrs of the air.

When the motor-driven aeroplane at last came, inventors paid less and less attention to birds. The construction of flying ma- chines was reduced to a problem in engi- neering. And so the aeroplane became less and less bird-like. In the hands of Wright and Curtiss it assumed the form of a box- kite with a man and motor perched on the lower edge. Soon it was found that such a construction off^ered too much resistance

��well worth copying they are. Although he may not have had it in mind, young White has vindicated Lillienthal. Every aero- plane designer must envy the modeling of White's glider.

Lillienthal took great pains to explain that if a bird is merely copied and enlarged, it becomes either too heavy or too weak to fly. This is a matter of structural size and strength. How White has made his arti- ficial dove strong and light enough to serve as a gliding machine without prominent stay posts and wires remains a question. But even if White's glider serves no other purpose than that of setting the flying efficiency of a bird's shape into bold relief, it is worthy of all praise. Assuming that the structure is strong enough, the flat gliding angle and the perfect shape of the body would insure efficient flight. Like Lillienthal, White must throw his body from side to side in order to balance him- self. But balancing in this fashion ought to be easy for White. Lillienthal himself pointed out that a bird easily shifts its weight or rather muscular effort (the same thing in this instance) to both wings or fore and aft in order to control itself side- wise and lengthwise. — Carl Dienstbach.

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